Question about Shooting over a Hill

B. What is the range of the projectile, ?
Express the range in terms of , , and .

Consider your advice to an artillery officer who has the following problem. From his current position, he must shoot over a hill of height at a target on the other side, which has the same elevation as his gun. He knows from his accurate map both the bearing and the distance to the target and also that the hill is halfway to the target. To shoot as accurately as possible, he wants the projectile to just barely pass above the hill.

A. Find the angle above the horizontal at which the projectile should be fired.
Express your answer in terms of and .

B. What is the initial velocity?
Express in terms of , , and .

C. Find , the flight time of the projectile.
Express the flight time in terms of and .